the size of that massive search area looking even more daunting overnight. The area off the Australian coast they're looking for is the size of France. And this is all up against a ticking clock, those batteries on the plane's black boxes running down, less than 20 days left right now. Time is of the essence and there's a bit of an amazing piece of information we want to share. 3 million people have actually joined the search from their own homes to find the plane. One satellite company posting new images online every day. Now being called the largest ground sourcing project of its kind. Every bit of it. Right to the latest on the search. The longest in modern aviation history and David Kerley is here with that. Reporter: What a mystery. Let's talk about the search. The potential area. Two so-called corridors which have been the last location of the 777 anywhere along there, we're talking about 2.25 million square nautical miles and told that's not where we should focus but here off the coast of Australia. This I've now provided us this map of the search area off Australia. But even this is about the size of Texas. The search covering a massive area is a bit of a race. Already a third of the battery life of those black box pingers is gone. This morning, that highly sophisticated subhunter from the United States, the p-8 has joined in the search efforts along the southern arc off the western coast of Australia. The search area. Reporter: This is where sores tell ABC news is the focus. The Australians have flown over parts of the ocean already. This search will be difficult. The sheer size of the search area poses a huge challenge. The search area is more than 600,000 square kilometers. Reporter: U.s. And other countries are still looking in the waters to the north, as well. We flew along as a p-3 subhunter scoured the waters of the bay of bengaling looking for any sign. Investigators say they cannot rule out decompression of the aircraft but still believe this was a deliberate act, as ABC news reported, at least 12 minutes before the last radio call someone programmed that hard left turn off the route to beijing. It was two minutes after who was thought to be the co-pilot says "All right, good night" to air traffic controllers that the location transponder is shut off and then that turn. From beijing where families are waiting for news, the Chinese reported this morning that they have found no links to terrorism among their citizens on the jet. Two-thirds of the 239 people on board were Chinese. The most crucial part of the investigation remains finding any of the jetliner's debris hoping one piece could lead investigators to the plane's main components and all-important black boxes. So to the two main points as we've been reporting at ABC news for the past couple of days somebody programmed that computer by a single source a long time before that last radio call and even the Malaysians are saying this is the special focus of the search for this missing plane, George. But still such a wide zone. Thanks very much.

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